Constrained optimization recently has been implemented in the LISREL software package, allowing formulation of parent-offspring transmission models in a simple and efficient manner. A reverse path model of parental transmission is described within the LISREL framework for application to twin and/or adoptive family data. The model incorporates genetic and environmental parameter constraints arising from assortative mating and cultural transmission. An illustration of the LISREL model is given using measures obtained from twins and parents involving fear of social cirticism.
Key Words LISREL - constrained parameters - twin-parent design - adoption design
An earlier version of this paper was described at the Third International Workshop on Twin Methodology in Boulder, Colorado, July 23–27, 1990. The paper was written while the first author was supported by Training Grant HD-07289 from the National Institute of Child Health and Human Development (NICHD) and by a grant from the John D. and Catherine T. MacArthur Foundation. Model development was supported in part by NICHD Research Grant HD-10333 and by research grant (MH-43899) from the National Institute of Mental Health. Preparation of the manuscript was facilitated by Grant RR-07013 awarded to the University of Colorado by the Biomedical Research Support Grant Program, Division of Research Resources, National Institutes of Health. Analyses of the data were facilitated by the BRSG grant RR-07013-25 awarded to the University of Colorado by the Biomedical Research Support Grant Program, Division of Research Resources, National Institutes of Health.
The model was developed using a beta-test version of LISREL 8. The LISREL 8 package is tentatively scheduled for commercial release in Summer 1992.